Method for controlling a processing system

ABSTRACT

Subfab components of the processing system may be controlled based on the flow of materials into the processing system. In some embodiments, the flow of an inert gas used to dilute the effluent gases may be controlled in accordance with the flow of one or more precursor gases. Thus, the cost of running the processing system is reduced while mitigating critical EHS concerns.

CLAIM OF PRIORITY UNDER 35 U.S.C. 119

This application claims priority to U.S. Provisional Patent Application Ser. No. 62/159,074, filed on May 8, 2015, which herein is incorporated by reference.

BACKGROUND

Field

Embodiments described herein generally relate to the manufacture of electronic devices, and more particularly, to methods for controlling a processing system.

Description of the Related Art

The manufacture of electronic devices by a processing system typically results in the creation of byproduct effluent gases. These effluent gases may contain undesirable species which may be harmful and/or hazardous. The concentration of the undesirable species in the effluent gases may be diluted, and the dilution is typically performed by subfab components, such as vacuum pumps, point-of-use (POU) abatement and heat removal devices. The subfab components are typically designed to manage worst-case risk scenarios in order to mitigate critical environmental, health and safety (EHS) concerns. As such, many subfab components may be operating continuously with virtually no downtime.

Therefore, an improved method for operating the subfab components is needed.

SUMMARY

Embodiments described herein generally relate to methods for controlling a processing system. In one embodiment, a method includes flowing a precursor gas into a processing chamber, flowing an inert gas into an exhaust line coupled to the processing chamber, and controlling the flow of the inert gas based on the flow of the precursor gas.

In another embodiment, a method includes flowing a precursor gas into a processing chamber at a first flow rate, flowing an inert gas into an exhaust line coupled to the processing chamber at a second flow rate, changing the first flow rate to a third flow rate, and changing the second flow rate to a fourth flow rate based on the changing of the first flow rate to the third flow rate.

In another embodiment, a method includes flowing a precursor gas into a processing chamber, flowing a coolant to an abatement system downstream of the processing chamber, and controlling the flowing of the coolant based on the flowing of the precursor gas.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

FIG. 1 schematically illustrates a processing system according to one embodiment.

FIG. 2 schematically illustrates a processing system according to another embodiment.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.

DETAILED DESCRIPTION

Embodiments described herein generally relate to methods for controlling a processing system. Particularly, subfab components of the processing system may be controlled based on the flow of materials into the processing system. In some embodiments, the flow of an inert gas used to dilute the effluent gases may be controlled in accordance with the flow of one or more precursor gases. Thus, the cost of running the processing system is reduced while mitigating critical EHS concerns.

In one embodiment, a method includes flowing a precursor gas into a processing chamber, flowing an inert gas into an exhaust line coupled to the processing chamber, and controlling the flow of the inert gas based on the flow of the precursor gas.

In another embodiment, a method includes flowing a precursor gas into a processing chamber at a first flow rate, flowing an inert gas into an exhaust line coupled to the processing chamber at a second flow rate, changing the first flow rate to a third flow rate, and changing the second flow rate to a fourth flow rate based on the changing of the first flow rate to the third flow rate.

In another embodiment, a method includes flowing a precursor gas into a processing chamber, flowing a coolant to an abatement system downstream of the processing chamber, and controlling the flowing of the coolant based on the flowing of the precursor gas.

FIG. 1 schematically illustrates a processing system 100 according to one embodiment. As shown in FIG. 1, the processing system 100 may generally include a processing chamber 102 having an interior processing volume 103, one or more gas inlets 105 coupled to one or more gas sources 124, and an outlet 107 coupled to a vacuum pump 112 via an exhaust line 116. The one or more gas sources 124 may provide one or more gases to the processing chamber 102, such as precursor gases, cleaning gases, etching gases, purge gases, or the like. The vacuum pump 112 is generally used to remove materials such as effluent gases from the processing chamber 102. The vacuum pump 112, in combination with a valve 108 disposed in the exhaust line 116, can also be used to control the pressure in the processing chamber 102.

A subfab component, such as a pump 114, may be utilized to pump an inert gas, such as nitrogen gas, into the exhaust line 116 via a conduit 115 in order to dilute the effluent gases. The diluted effluent gases may be fed into an abatement system 113 downstream of the processing chamber 102. Conventionally, the pump 114 is operated continuously and the flow of the inert gas is set at a maximum value. The dilution of the effluent gases reduces the risk that accidental leaks will result in a pyrophoric reaction. However, large flows of inert gases call for more abatement energy to process the diluted effluent gases. In order to reduce the cost of operating the subfab components and to abate the effluent gases more efficiently, a controller 106 may be utilized.

The controller 106 may be coupled to receive a flow rate or flow rates from the one or more gas sources 124 or a mass flow controller (not shown) located in the conduit between the one or more gas sources 124 and the processing chamber 102. The controller 106 may be also coupled to send set points to the subfab components, such as the pump 114. The subfab components, such as the pump 114, may be controlled by the controller 106 based on the flow of the gases from the one or more gas sources 124 into the processing chamber 102. In one embodiment, the flow of an inert gas used to dilute the effluent gases may be controlled in accordance with the flow of one or more precursor gases into the processing chamber 102. In some embodiments, PID type algorithms may be utilized to control the flow of the inert gas used to dilute the effluent gases based on the flow of one or more precursor gases. For example, the flow of the inert gas may be set in proportion to the flow of the precursor gases. In one embodiment, a silane based precursor gas is flowed into the processing chamber 102 from the gas source 124. Because the harmful or hazardous species in the effluent gases are produced as a result of having the silane based precursor gas, the flow of the silane based precursor gas may be used to control the subfab components. During processing, the silane based precursor gas may be flowed into the processing chamber 102 at a first flow rate, which is sent to the controller 106. The controller 106 may signal the pump 114 to inject an inert gas, such as nitrogen gas, into the exhaust line 116 via the conduit 115 at a second flow rate based on the first flow rate of the silane based precursor gas. If the flow rate of the silane based precursor gas is increased or decreased, the flow rate of the inert gas pumped into the exhaust line 116 may be adjusted accordingly by the controller via the pump 114, for example in proportion to the flow rate of the silane based precursor gas. For example, if the flow rate of the silane based precursor gas is decreased, the flow rate of the inert gas is also decreased. In addition, if the flow of the silane based precursor gas into the processing chamber 102 is paused, the flow of the inert gas into the exhaust line 116 may be also stopped. By varying the flow rate of the inert gas into the exhaust line 116 based on the flow rate of the silane based precursor gas, the cost of operating the subfab components, such as the pump 114, is reduced. Additionally, the efficiency of abating the diluted effluent gases is improved.

It should be noted that in an embodiment wherein the flow rate of inert gas is controlled in proportion to the flow rate of a precursor gas, such as the silane based precursor gas above, the proportionality may be dynamically adjusted based on process requirements. For example, at very low flow rates of the silane based precursor, the proportionality of the inert gas flow rate may be reduced, and at high flow rates of the silane based precursor, the proportionality of the inert gas flow rate may be increased. In this way, flow rate of the inert gas may be controlled in proportion to the flow rate of the precursor gas, but the flow rate of the inert gas may increase faster than the flow rate of the precursor gas to mitigate the increased risk associated with increased flow rates of precursor gases.

In some cases, the flow rate of inert gas may be based on flow rates of more than one precursor gas. For example, a first flow rate may be determined based on a flow rate of a first precursor, a second flow rate may be determined based on a flow rate of a second precursor, and the flow rate of inert gas may be determined by a combination of the first flow rate and the second flow rate. The first flow rate may be determined in proportion to the flow rate of the first precursor, or by any combination of proportional, integral, or derivative control. The second flow rate may likewise be determined in proportion to the flow rate of the second precursor, or by any combination of proportional, integral, or derivative control. The combination of the first flow rate and the second flow rate may be simple addition, or may be linear or non-linear combination that reflects, for example, different levels of risk associated with the different precursors. If the first precursor has a higher level of risk than the second precursor, that higher level of risk may be reflected by a different proportionality constant for determining the first flow rate and the second flow rate, or by a linear or non-linear combination that weighs the risk of the first precursor more than that of the second precursor.

The controller 106 may include a central processing unit (CPU) 118, a memory 120, and support circuits 122 for the CPU 118. The memory 120 may be one or more of readily available memory such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, flash, or any other form of digital storage, local or remote. The support circuits 122 are coupled to the CPU 118 for supporting the CPU 118. The support circuits 122 may include cache, power supplies, clock circuits, input/output circuitry and subsystems, and the like.

FIG. 2 schematically illustrates a processing system 200 according to one embodiment. As shown in FIG. 2, a pump 202 may be coupled to the abatement system 113 in order to pump a coolant, such as water, to the abatement system 113 downstream of the processing chamber 102. Again, conventionally the coolant may flow continuously at a maximum flow rate within the abatement system 113 to provide cooling of the abatement system 113. In order to reduce the cost of operating the pump 202, the controller 106 is electrically coupled to the pump 202 to control the flow rate of the coolant based on the flow of the gases from the one or more gas sources 124 into the processing chamber 102. The controller 106 may control the pump 202 using similar methods as for controlling the pump 114. For example, if the flow rate of the gas or gases flowing into the processing chamber 102 is decreased, the flow rate of the coolant to the abatement system 113 is also decreased. In some embodiments, the pump 114 (FIG. 1) is included in the processing system 200, and the pump 114 may be controlled by the controller 106, as described in FIG. 1.

In addition to the pumps 114, 202, the controller 106 may additionally control other subfab components, such as pump for an air handling system that generates compressed air, based on the flow of the gas or gases into the processing chamber. Thus, the subfab components that are controlled by the controller are operated more efficiently and at a lower cost.

While the foregoing is directed to embodiments, other and further embodiments may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. 

The invention claimed is:
 1. A method, comprising: flowing a precursor gas into a processing chamber; injecting an inert gas directly into an exhaust line at a location between the processing chamber and an abatement system downstream of the processing chamber, wherein the inert gas bypasses the processing chamber; and controlling the flow of the inert gas based on the flow of the precursor gas, wherein the flowing of the inert gas is controlled in response to a change to the flowing of the precursor gas.
 2. The method of claim 1, wherein the precursor gas is a silane based precursor gas.
 3. The method of claim 2, wherein the inert gas is nitrogen gas.
 4. The method of claim 1, wherein the controlling the flow of the inert gas is performed by a controller controlling a subfab component coupled to the exhaust line.
 5. The method of claim 4, wherein flow rates of the precursor gas into the processing chamber are sent to the controller.
 6. The method of claim 5, wherein the controller uses PID algorithms to control the flow of the inert gas based on the flow of the precursor gas.
 7. The method of claim 1, wherein a proportionality of the flow of the inert gas to the flow of the precursor gas is dynamically adjusted.
 8. A method, comprising: flowing a precursor gas into a processing chamber; injecting a coolant directly into an abatement system downstream of the processing chamber, wherein the coolant bypasses the processing chamber; and controlling the flowing of the coolant based on the flowing of the precursor gas, wherein the flowing of the coolant is controlled in response to a change to the flowing of the precursor gas.
 9. The method of claim 8, wherein the precursor gas is a silane based precursor gas.
 10. The method of claim 8, wherein the controlling the flow of the coolant is performed by a controller controlling a subfab component coupled to the abatement system.
 11. The method of claim 10, wherein flow rates of the precursor gas into the processing chamber are sent to the controller.
 12. The method of claim 11, wherein the controller uses PID algorithms to control the flow of the coolant based on the flow of the precursor gas.
 13. The method of claim 1, wherein the flowing of the precursor gas is at a first flow rate, and the inert gas is injected into the exhaust line at a second flow rate.
 14. The method of claim 13, wherein the change in the flowing of the precursor gas comprises an increase in the first flow rate, and the controlling the flow of the inert gas comprises increasing the second flow rate.
 15. The method of claim 13, wherein the change in the flowing of the precursor gas comprises a decrease in the first flow rate, and the controlling the flow of the inert gas comprises decreasing the second flow rate.
 16. The method of claim 1, wherein the location of the injection of the inert gas is between a pump and the abatement system. 